File Attachments

Each topic can have one or more files of any type attached to it by using the Attach screen to upload (or download) files from your local PC. Attachments are stored under revision control: uploads are automatically backed up; all previous versions of a modified file can be retrieved.

What Are Attachments Good For?

File Attachments can be used to create powerful customized groupware solutions, like file sharing and document management systems, and quick Web page authoring.

Document Management System

You can use Attachments to store and retrieve documents (in any format, with associated graphics, and other media files); attach documents to specific TWiki topics; collaborate on documents with full revision control; distribute documents on a #AttachmentAccessneed-to-know basis using web and topic-level access control; create a central reference library that"s easy to share with an user group spread around the world.

File Sharing

For file sharing, FileAttachments on a series of topics can be used to quickly create a well-documented, categorized digital download center for all types of files: documents; graphics and other media; drivers and patches; applications; anything you can safely upload!

Web Authoring

Through your Web browser, you can easily upload graphics (or sound files, or anything else you want to link to on a page) and place them on a single page, or use them across a web, or site-wide.

NOTE: You can also add graphics - any files - directly, typically by FTP upload. This requires FTP access, and may be more convenient if you have a large number of files to load. FTP-ed files can"t be managed using browser-based Attachment controls. You can use your browser to create TWikiVariables shortcuts, like this %H% = .

Uploading Files

Click on the Attach link at the bottom of the page. The Attach screen lets you browse for a file, add a comment, and upload it. The uploaded file will show up in the #FileAttachmentTableFile Attachment table.

NOTE: The topic must already exist. It is a two step process if you want to attach a file to a non-existing topic; first create the topic, then add the file attachment.

Any type of file can be uploaded. Some files that might pose a security risk are renamed, ex: *.php files are renamed to *.php.txt so that no one can place code that would be read in a .php file.

The previous upload path is retained for convenience. In case you make some changes to the local file and want to upload it, again you can copy the previous upload path into the Local file field.

TWiki can limit the file size. This is defined by the %ATTACHFILESIZELIMIT% variable of the TWikiPreferences, currently set at 10000 KB.

It"s not recommended to upload files greater than a few hundred K through a browser. Large files can be extremely slow-loading, and often time out. Use an FTP site for large file uploads.

Downloading Files

Click on the file in the #FileAttachmentTableFile Attachment table.

NOTE: There is no access control on individual attachments. If you need control over single files, create a separate topic per file and set topic-level TWikiDocumentation#TWikiAccessControlaccess restrictions for each.

The first table is a list of all attachments, including their attributes. An h means the attachment is hidden, it isn"t listed when viewing a topic.

The second table is all the versions of the attachment. Click on View to see that version. If it"s the most recent version, you"ll be taken to an URL that always displays the latest version, which is usually what you want.

To change the comment on an attachment, enter a new comment and then click Change properties. Note that the comment listed against the specific version will not change, however the comment displayed when viewing the topic does change.

To hide/unhide an attachment, enable the Hide file checkbox, then click Change properties.

Known Issues

Unlike topics, attachments are not locked during editing. As a workaround, you can change the comment to indicate an attachment file is being worked on - the comment on the specific version isn"t lost, it"s there when you list all versions of the attachment.